A Union Jack patch shone brightly on a man’s soiled clothing as his corpse was hauled from the loam and laid atop a leopard-print blanket on a fine Autumn afternoon just outside Kharkiv.

Sergiy Lutsay had been able to examine the corpse – a civilian to judge from his shoes and clothing – when Russian soldiers forced him to bury it and another body back in March, the 40-year-old local told Ukrainian police on Friday.

While the identity of the bodies remained a mystery, Kharkiv police chief Volodymyr Tymoshenko suspected war crimes. The men bore signs of torture and the ears of at least one had been severed, he told reporters, though this was not obvious given the advanced state of decay.

An unknown fate met in an undistinguished hamlet called Hrakove might have remained an anonymous tragedy were it not uncovered during a surprise lightning offensive this week that may prove to be a major moment in the war.

This week has seen Ukrainian forces break a months-long stalemate on one of the war’s principal frontlines in the country’s northeast.

Hrakove, a cluster of war-damaged houses around a church at a crossroads, is part of a wide swathe of Kharkiv region that Ukrainian forces have now freed from Russian occupation, including the strategically significant cities of Izium and Kupyansk.

On Saturday, Moscow acknowledged withdrawing from Izium, a retreat that may well mark Russia’s biggest loss of territory since its forces were forced to abandon their assault on the capital Kyiv in March.

Residents in Russian-controlled parts of the Kharkiv region have been advised to evacuate to Russia, according to state-run news agency TASS.

The rapid advance meant that media taken on an organised trip to Hrakove on Friday, two days after its liberation, was shown an area already far behind front lines – Ukrainian forces had already advanced a further 40 miles eastwards into Kupyansk, Mr Tymoshenko told reporters.

By Saturday, the counteroffensive had turned into a widespread rout of Russian forces from Kharkiv district, leaving Ukrainians ecstatic, pro-Russian commentators despondent and analysts and journalists struggling to keep up.

Nearly 1,000 square miles of territory had been recaptured by Friday, according to the Institute for the Study of War, a figure that does not take into account Izium and Kupyansk.

Many details remained hazy amid a strict media blackout, with occasional official announcements supplemented by triumphant videos posted online showing Ukrainian soldiers hoisting flags in “de-occupied” towns in the Kharkiv region and being greeted by grateful locals.

In Moscow’s first official acknowledgement of the scale of the defeat there, Russia’s defence ministry announced it was “regrouping” on Saturday.

“To achieve the goals of the special military operation to liberate Donbas, a decision was made to regroup Russian troops stationed in the Balakliya and Izium regions, to bolster efforts along the Donetsk front,” Russia’s defence ministry said in a statement.

“A number of distraction and distracting activities were carried out to disguise the real actions of the troops,” it added, in comments that were widely mocked online.

Liberating Izium in particular represents a major and unexpected victory for Ukrainian forces.

“It’s a strategic point both for both sides,” Izium councillor Maxim Strelnyk told The Telegraph earlier this week, calling his city “the gate to the Donbas region” and the ongoing Ukrainian operation to liberate it “genius”.

In particular, Hora Kremenets, a high point on the right bank of the Siversky Donets River south of Izium, offers a commanding field of fire over the surrounding region, he said. “Whoever holds this point can control the surrounding area for 60km,” Mr Strelnyk said.

The liberation of nearby Kupyansk, where Ukrainian soldiers uploaded photos of themselves raising their flag, is also important as it gives Kyiv control over railway lines Russia had used to supply its forces in eastern Ukraine.

The blitzkrieg appears to have caught Russian forces unprepared after they moved troops down to reinforce Kherson in response to a widely telegraphed Ukrainian counteroffensive in the south.

“It’s well known that war is the art of lies,” Mr Strelnyk said. “Our forces managed to fool the other side, we drew them out in one direction and then struck in another place.”

“Russian forces were likely taken by surprise,” the British Defence Ministry said in its Saturday update. “The sector was only lightly held.”

The Ukrainian offensive in Kherson was “probably a diversion”, according to Mika Mäenpää, a Finnish artillery officer and military analyst. “This apparently caused Russia to critically undermine the Kharkiv front,” he wrote on Twitter.

Moscow desperately attempted to rush reinforcements into the breach, including reportedly using Mi-26 helicopters to fly troops and armoured vehicles into Izium and Kupyansk.

The head of the Russian-installed administration in the province’s occupied areas, Vitaliy Ganchev, acknowledged the “fierce battles” in televised remarks, saying “now Russian reserves have been brought there, our troops are fighting back”.

The speed of the Ukrainian advance left the Kremlin’s media reeling. “The news is troubling,” Russian television anchor Olga Skabeyeva said, blaming the advance on Western support to Ukraine. “For its advance in the Kharkiv front, Ukrainian forces used the units that have been trained in Britain.”

Russia responded to the offensive with a series of strikes on Kharkiv and surrounding towns on Saturday and earlier in the week.

Earlier, The Telegraph visited a Ukrainian hospital where a Russian missile had exploded on the grounds, with police saying the healthcare facility was targeted because it was treating wounded Ukrainian soldiers.

While Ukraine has released no information about losses, casualties are likely to be high, with dozens of ambulances seen travelling to and from frontlines.

Videos shared online show Ukrainian forces have been taking prisoners, while automatic text messages sent to phones in the Kharkiv region call on Moscow’s troops to give up. “Russian soldier, if you want to live – surrender!” read one message. “Your brothers in arms already gave up their weapons and wait for exchange.”

Simultaneous Ukrainian attacks in the eastern Donbas region and the southern Kherson front raise the prospect of even wider gains against stretched and demoralised Russian forces in the coming days.

There were also reports of heavy fighting around nearby Lyman and Lysychansk, in the north of the Donbas region.

Denis Pushilin, head of the pro-Russian separatist Donetsk People’s Republic, said the situation in Lyman was “very difficult” and that there was also fighting in “a number of other localities”, particularly in the northern part of the region.

There were also reports that Ukrainian forces had retaken Donetsk airport, another potentially massive victory if confirmed.

Already some Ukrainian civilians are celebrating. Mr Lutsay, who was forced to bury the bodies in Hrakove, prepared a celebratory meal on Friday of Olivier salad – a dish of finely diced potatoes, peas, carrots and other vegetables – in the basement below his destroyed apartment where he and his elderly father had sheltered for four months.

“Of course we’re happy,” he said. “What other reaction could we have?”

Source: Telegraph.co.uk